Variable camber flap end seal

ABSTRACT

An end seal (36) for a variable camber flap in which the seal is formed of an upper portion (52) including closely spaced fingers (56). The fingers extend generally vertically downwardly from adjacent a flexible surface (40) of a flap (20). There are lower sealing walls (94, 96) extending generally vertically upwardly from adjacent the bottom of the flap (106). The lower sealing walls are adapted to remain in sealing engagement with the fingers as the camber of the flap is varied by increasing the curvature as it is lowered from a normally upper position.

The Government has rights in this invention pursuant to contract No.F33615-78-C-3027 awarded by the U.S. Air Force.

DESCRIPTION

1. Technical Field

This invention relates to variable camber flaps and end seals therefor,as may be used on aircraft wings or other aerodynamic structures.

2. Background Art

In the use of variable camber flaps on aircraft wings, in the upper orcruise position, the upper surface of the flap has a nominal fore andaft camber. When the flaps are lowered, the camber of the upper surfaceis substantially increased.

In the development of variable camber flaps, it was found that largeboundary displacements occurred as the flaps were raised and lowered. Itwas also found that new types or methods of sealing the flap ends wererequired in order to protect the actuation mechanisms and equipment fromwater and other contaminants, and to make the surfaces aerodynamicallyefficient.

Thus, it was determined that flap end seals must restrict the entranceand entrapment of water. It was also found that spanwise airflow intothe flaps must be restricted to the maximum practical extent.

Attempts had been made to make end seals out of sponge rubber, the sealsbeing in the form of upper and lower parts, but this presented theproblem of requiring a number of rotating plates and links tying themtogether. The sponge rubber is also subject to abrasion and weatheringwhich would require frequent disassembly and reassembly.

A search of the patent literature discloses a number of seals which arenot directly pertinent. The closest approach to the present inventionfound is in U.S. Pat. No. 2,792,599 in that it discloses a multiplefinger concept but the finger elements are not adapted to cooperate witha channel or similar structure as in the present invention.

The following U.S. Pat. Nos. disclose various forms of seals: 2,671,935,2,722,978, 2,728,982, 2,792,599, 3,048,356, 3,175,791, 3,589,070,3,706,173.

DISCLOSURE OF THE INVENTION

The invention is an end seal for a variable camber flap and an end sealin combination with the flap in which an upper seal portion of closelyspaced sealing members in the form of fingers extend generallyvertically downwardly from adjacent the top of the flap. The top of theflap is flexible so that when the flap is lowered, the camber curvatureof the top is substantially increased.

The leading end of the flap is adapted to be fixed to an aircraft wing,for example. The lower surfaces of the flap are articulated and the flapis lowered and raised by linkage means therein.

Lower sealing means generally in the form of upwardly extending channelwalls are associated with the lower surfaces and are adapted to receivethe closely spaced sealing members extending downwardly from the top inslidable and sealing engagement. The lower sealing means support theclosely spaced sealing members in sealing engagement as the camber ofthe flap is varied to increase the curvature as it is lowered from anormal cruise position to a takeoff or landing position, for example.

The closely spaced sealing members or fingers have gaps therebetweenformed by slots which extend from a lower end of the fingers to an upperplate portion at an angle to the fingers and the slots terminate in astress relief hole in the plate portion. The slots taper upwardly fromthe lower end and have an angle of about two degrees when the flap is ina normal upper cruise position, and the slots are closed orsubstantially closed when the flap is lowered and the curvature of thecamber is increased.

End seals according to the invention are positioned at least on one spanend of each flap and are provided to prevent contamination of the flapmechanism and to improve aerodynamics of the flap. The spacing betweenthe fingers is such to accommodate the flexing of the top surface, theslots being minimized in width to admit a minimum of airflow into theflap.

The seal has the advantage of being a simple single joint to makepossible low manufacturing and assembly costs and unlikely failure undernormal load conditions. It provides excellent sealing efficiency with aminimum maintenance due to very little abrasion. The sliding arrangementbetween the upper and lower sealing parts provides the advantages ofproducing an excellent seal, and yet, being flexible enough to survivesubstantial warpage of the upper and lower parts.

Further advantages of the invention may be brought out in the followingpart of the specification wherein small details have been described forthe competence of the disclosure, without intending to limit the scopeof the invention which is set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the accompanying drawings which are for illustrativepurposes:

FIG. 1 is a plan view of an aircraft wing having three flaps, accordingto the invention, and end seals at five ends of the flaps;

FIG. 2 is a fragmentary partially cutaway and partially cross-sectionalview illustrating the configuration of the upper and lower membersforming the end seal;

FIG. 3 is an end view of a flap having an end seal according to theinvention, the flap being in its fully-up position, taken along the line3--3 in FIG. 1;

FIG. 4 is an end view of the flap as shown in FIG. 3 in the fully-downposition, illustrating the camber variation, the increase in curvature,the flexibility of the flap, and the operation of the sealing mechanism;

FIG. 5 is a fragmentary end view illustrating the sliding sealingengagement of the upper and lower sealing members of the end seal, takenalong the line 5--5 in FIG. 2;

FIG. 6 is a cross-sectional end view of a flap illustrating a linkagesystem which serves to raise and lower the flap; and

FIG. 7 is a fragmentary end view illustrating another embodiment of alower portion of the end seal.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring again to the drawings, there is shown in FIG. 1 a plan view ofan aircraft wing 10 having a leading edge 12 and outboard edge 14, andthree variable camber flaps 16, 18 and 20 forming a substantial portionof the trailing end of the wing. The flaps 16, 18 and 20 are fixed to atrailing end 22 of the wing 10.

The outboard flap 16 has an outwardly tapering end 24, permanentlyclosed and adapted to flex with the upper and lower sides of the flap asit is moved upwardly and downwardly, during which times the camber isvaried. There are five seals 30, 32, 34, 36 and 38 on respective ends ofthe flaps 16, 18 and 20, according to the invention, FIG. 1. The sealsare identical and the seal 36 is specifically shown in detail in FIGS.2-5.

The flap 20 is shown in its fully up position in FIG. 3. Its uppersurface is in nominal camber and it is formed of a flexible fiberglassplate portion 40 and a rigid slightly curved trailing edge beam portion42. The flexible plate 40 may extend forwardly to directly trail therearward end of the aircraft wing 10 or may trail from the vicinity of asupport at 44. In any event, the flexible plate 40 is intermediate theends of the flap 20. The forward end of the flap is fixably secured tothe trailing end 22 of the wing by upper and lower spars 48 and 50.

As best seen in FIGS. 2 and 5, an upper, fiberglass, inverted L-shapedportion 52 of end seal 36 has a generally horizontally short leg 54 andan elongated generally vertical leg 56. The upper leg 54 is secured tothe fiberglass top plate 40 by means of fasteners 60 through holes 62and may in addition be bonded as at surface 64, FIG. 2. The length ofthe individual fingers, as 66, at the leading end, and 68, at thetrailing end, FIG. 3, is dependent upon the requirements of theengagement of the upper portion 52 of the seal with an aluminum lowerportion 70 of the seal. As shown in FIG. 3, in the fully-up position,the fingers are spaced at 72 by an upwardly extending taper, the spaceshaving an angle of no less than two degrees in the fully-up position.The spaces 72 terminate in leg 54 in stress relief holes 74, to relieveany stress that may develop in the fingers. The holes and slots 72 areabout one inch apart. Inboard and outboard surfaces 80 and 82 of thefingers are coated with Teflon lubricant for easy sealing engagementwith the lower portion 70 of the seal.

The fingers 56 of the upper sealing portion are slidably sealinglyengaged and supported in lower portion 70 of the seal, formed ofchannels 90 and 92. The channels have upwardly extending legs 94, 96 and98, 100, respectively. The legs 96, 94 are formed as upper portions ofL-shaped members having horizontal short legs 102 and 104, secured to alower bottom forming, skin plate 106 of the flap 20. The legs of thechannel 92 are similarly secured and supported on a second plate 108. Athird plate 110 forms the bottom of the trailing edge beam 42.

As best seen in FIGS. 2-4 and 6, the plates overlap their ends at 112and 114 to form closures in the bottom of the flap, and forward end 116of the plate 106 is slidably engaged with a fixed closure plate 120,attached to the spar 50. Above 112 and 114, FIGS. 2, 3, and 4, there areinsignificant gaps 118 and 122, relative to the seal, at forward andrearward ends of the channel legs.

Inwardly of the legs 102 and 104 of the channel 90 is a horizontalsupport portion 124 secured to the bottom plate 106. Extending upwardlyfrom the portion 124 is a vertical support member 126 and it extendsupwardly adjacent the forward fixed end of the flap to the underside ofthe fixed portion of the top 40, secured to hold forward lower and upperplates of the flap together.

As shown in FIG. 6, the flap is raised and lowered when the camber isvaried by a linkage system, generally designated as 130. The linkagesystem is operated by a rotary acutator 132, not shown in detail,supported on fitting 134 and spars 48, 50 and having a driving shaft136. It extends spanwise across the flap to operate a series of spanwisespaced linkage elements 140, FIG. 1.

In FIG. 6 the linkage system is shown to have fully lowered the flapfrom its fully up position shown in phantom outline, and hassubstantially varied the camber of the flexible fiberglass top portion40 increasing its curvature. The fiberglass is fixed to the trailingedge beam 42 so that a continuous curve is formed along the twoportions. In the operation of the linkage system, the actuator 132pivots a main beam 146 at a forward end 148, pivoted on 134, by actionof beam 152 connected to rotate with the actuator. As the actuator shaft150 rotates clockwise, the beam 152 is lowered so as to lower connectinglink 154 and the beam 146. The after end of the beam 146 is pivotallyconnected at 156 to beam 160, connected at 162 to the trailing edge beam42 so that the latter moves with and is supported by the beam 160. Thebeam 160 is pivotally connected to link 164 which in turn is pivotallyconnected to the flexible top portion 40, again connecting the top andbottom of the flap. The pivot 156 is also connected to the plates 106and 108 to support them. The forward end of the beam 160 is connected toa short link 168 which is connected to a link 170 operated by the link154.

Thus, when the link 154 is moved downwardly, the beam 146 is moved asubstantial amount compared with the downward movement of the link 168,and the beam 160 and link 162 move accordingly, downwardly.

To raise the flap, the shaft 150 is rotated counterclockwise causing thelinks 154 and 168 to be moved upwardly. This in turn causes the pivotpin 162 to be moved upwardly so as to move the trailing end of the flapto its fully-up position. During this movement, the link 164 is alsoraised to rotate the flexible portion 40 directly above the link 164.Similarly, the beam 152 and link 170 are moved upwardly to raise thesurface of the flexible member 40 directly.

When the flap is in the fully up position, FIG. 3, the outer legs of thechannels 90 and 92 substantially cover the fingers and the gaps 72therebetween, to form a good seal on the flap end to preventcontamination of the flap mechanism and to improve the aerodynamics ofthe flap. As the flap is lowered by the linkage or other means such asby hand, the flexible portion of the flap top rearwardly of the support44 bends downwardly to increase the curvature of the camber, and gaps 72between the fingers are closed or substantially closed, as shown in FIG.4, to maintain a continuous seal when the channels and fingers moverelative to each other to expose a greater amount of the fingers. Theseal maintained by the fingers, remaining in sliding and supportedengagement within the legs of the channels, during the downward movementof the flap, is determined by the contacts of the fingers as the gaps 72are closed.

As the downward movement occurs, the bottom plate 106 of the flap slidesforwardly on and is supported by the rearward end of the plate 120.Similarly, the plates slide in a supporting relationship with respect toeach other at 112 and 114. When the flap is raised to the fully-upposition by the linkage mechanism or by hand, for example, the movementsof the parts are in reverse and the seal is maintained in the samemanner as indicated above.

The aluminum legs of the channel remain in sealing support against thefingers which are coated with Teflon lubricant and can be adjusted fortightness or looseness with respect to the fingers. If the fingers weartoo much, they are easily replaced by removing them from the topflexible plate 40.

In FIG. 7 a lightening embodiment of the invention is illustrated. Here,the flexible portion 40 of the top is secured to the fiberglass fingers56 in the same manner as shown in FIG. 5. Instead of a channel, a singlewall 180 of an L-shaped lower seal portion is in sliding contact withthe fingers. The lower seal is made of aluminum and has a lower leg 182which is secured to the bottom plate 106. For this embodiment analuminum stiffener 184 is secured to extend over the lower leg 182 toaid in maintaining it in place and to hold the single aluminum leg 180in sealing contact with the fingers. A similar single leg replaces thechannel 92, illustrated in the other embodiment. The aluminum leg 180 iseasily maintained in sliding adjustment against the sealing fingers 56.

The invention and its attendant advantages will be understood from theforegoing description and it will be apparent that various changes maybe made in the form, construction, and arrangements of the parts of theinvention without departing from the spirit and scope thereof orsacrificing its material advantages, the arrangements hereinbeforedescribed being merely by way of example. I do not wish to be restrictedto the specific forms shown or uses mentioned except as defined in theaccompanying claims.

I claim:
 1. In a variable camber flap, an end seal comprising:closelyspaced sealing members extending generally vertically downwardly fromadjacent and being associated with the top of the flap, said sealingmembers being between the forward and after ends of the flap; and lowersealing means extending generally vertically upwardly from adjacent andbeing associated with a bottom of the flap; said closely spaced sealingmembers being slidably and sealingly engaged with said lower sealingmeans; said lower sealing means being adapted to remain in sealingengagement with said closely spaced sealing members as the camber ofsaid flap is varied by increasing the curvature as it is lowered from anormally upper position.
 2. The invention according to claim 1 inwhich:said lower sealing means are in supporting contact with saidclosely spaced sealing members.
 3. The invention according to claim 1 inwhich:said lower sealing means is in the form of an upwardly openingchannel having two spaced legs in sealing contact with said closelyspaced sealing members.
 4. The invention according to claim 1 inwhich:said closely spaced sealing members are secured to the flapadjacent its top; said lower sealing means being secured to said flapalong bottom forming portions.
 5. The invention according to claim 4 inwhich:said closely space sealing members are fingers extending from anupper plate portion, the plate portion being secured to the flapadjacent the camber to vary therewith; said plate portion forming oneleg of an inverted L in cross section and the fingers forming the otherleg of the L.
 6. The invention according to claim 5 in which:the spacingbetween said fingers is formed by slots which extend from a lower endthereof into the plate portion and terminate in a stress relief holetherein.
 7. The invention according to claim 6 in which:said slotsbetween said fingers tapering upwardly from the lower end; said slotshaving an angle of about two degrees when the flap is in a normal uppercruise position; said slots being substantially closed when the flap islowered and the curvature of the camber is increased.
 8. The inventionaccording to claim 4 in which:said bottom forming portions arearticulated so that as the camber of the flap is varied the closelyspaced sealing members and the lower sealing means slide in sealingengagement relative to each other.
 9. A variable camber flapcomprising:a forward end of said flap adapted to be fixed to thetrailing end of an airfoil; a trailing end of said flap; an intermediateportion of said flap extending between the forward and trailing ends;said flap having a nominal fore to aft camber in an upper cruiseposition and being adapted to have an increased camber curvature in alowered down-flap position; an upper surface of said intermediateportion being flexible to receive the increased camber curvature in thelowered down-flap position; lower portions of said intermediate portionbeing articulated to move in accordance with the camber variation;linkage means within said flap to raise and lower said flap and toincrease the curvature of the flap as it is lowered and decrease thecurvature as it is raised; an end seal on at least one span end of theflap having closely spaced sealing members extending generallyvertically downwardly from adjacent and being associated with the uppersurface of the intermediate portion; and lower sealing means extendinggenerally vertically upwardly from adjacent and being associated withsaid lower portions of the intermediate portion; said closely spacedsealing members being slidably and sealingly engaged with said lowersealing means; said lower sealing means being adapted to remain insealing engagement with said closely spaced sealing members as thecamber of said flap is varied by increasing the curvature as it islowered and decreasing the curvature as it is raised.
 10. The inventionaccording to claim 9 in which:said lower sealing means are in supportingcontact with said closely spaced sealing members.
 11. The inventionaccording to claim 9 in which:said lower sealing means is in the form ofan upwardly opening channel having two spaced legs in sealing contactwith said closely spaced sealing members.
 12. The invention according toclaim 9 in which:said closely spaced sealing members are secured to theflap adjacent its top; said lower sealing means being secured to saidflap along said lower portions forming the bottom of said flap.
 13. Theinvention according to claim 12 in which:said closely spaced sealingmembers are fingers extending from an upper plate portion, the plateportion being secured to the upper surface of the intermediate portionto be varied with the camber thereof; said plate portion forming one legof an inverted L in cross section and the fingers forming the other legof the L.
 14. The invention according to claim 13 in which:the spacingbetween said fingers is formed by slots which extend from a lower endthereof into the plate portion and terminate in a stress relief holetherein.
 15. The invention according to claim 14 in which:said slotsbetween said fingers tapering upwardly from the lower end; said slotshaving an angle of about two degrees when the flap is in a normal uppercruise position; said slots being substantially closed when the flap islowered and the curvature of the camber is increased.
 16. The inventionaccording to claim 12 in which:said articulated lower portions beingpositioned so that as the camber of the flap is varied, the closelyspaced sealing members and the lower sealing means slide in sealingengagement relative to each other.